Alexander's case strongly contrasts the treatment and circumstances of the altercation between Trayvon Martin and George Zimmerman, which culminated in Zimmerman's acquittal on July 13 for Martin's death.

"There is something patently unjust about this. A woman who was not guilty of shooting or killing anyone is in jail for 20 years. A man who did kill someone is walking free. The gap is too great," Jackson said. "We see radical racial polarization in the judicial system. That's a cause of great concern. Alexander has already been in jail almost three years. At least I made our case on a moral appeal."

Alexander, once hospitalized after a brutal attack by then-husband, fired a warning shot after being attacked in another incident.

Under Florida's gun laws, she received a mandatory 20-year sentence despite the history of domestic violence in her marriage and a claim of self-defense under the state's "stand your ground" law.

Advocates for Alexander have been active in the press and on social networking sites since early last year, highlighting the contrast between support for Zimmerman during the Martin tragedy.

Similar cases have been overlooked. John McNeil, a Georgia African-American, is imprisoned after losing a "stand your ground" case in which a white man threatened McNeil's family at McNeil’s residence.

John White, a black father from New York, was jailed after killing a 17-year-old youth who joined a group of boys intent on harming White's teenage son at White's residence.